Product activation is a license validation procedure required by some computer software programs. Product activation is used to invalidate or severely restrict a product's functionality until the product is registered with a publisher by means of a special identification (activation) code or “product key”. Product activation often refers to a method where a software application or suite hashes hardware serial numbers and an ID number specific to the product's license (e.g., the product key) to generate a unique installation ID. The installation ID is sent to the manufacturer to verify the authenticity of the product key and determine that the product key is not being used for multiple installations. Other product key models are also used to enforce the purchase of a license for use of the software product.
Products may also have various activation states. An “un-activated” product usually acts as a time-limited trial until a product key is purchased. An “activated” product has its product key purchased and entered. Some products allow licenses to be transferred from one machine to another without deactivating the copy on the old machine before reactivating the software product on the new machine.
Most licensing systems provide a different license depending on the type of product being sold. For example, the license that accompanies a trial product is usually more limited in its scope than the license of a full or “perpetual” product. Beyond the license terms however, many current licensing systems enforce the license by not providing the full version of the product to the user. What is included on the CD or download of the software product is a trial version of the product. To obtain the full version of the product, a license for the full version would need to be purchased, and then the full version is supplied or downloaded to the user.